Uniquely shaped ophthalmological device

ABSTRACT

Disclosed is a medical valve comprising a pair of plates holding in tension a membrane folded over to form a chamber with an elongated, slit-like opening along adjoining edges. The plates include interlocking members which interlock the plates together. An inlet tube in communication with the chamber extends outwardly from the plates. The preferred configuration of the chamber is trapezoidal. Also disclosed is a surgical instrument that is a needle-like member having an elongated slot in the wall of this member. A method of using this instrument to implant a tubular element in the body of a patient is also disclosed.

RELATED PATENT APPLICATIONS

This application is a continuation-in-part application of U.S. Ser. No.07/786,734, entitled "Medical Valve," filed Oct. 1, 1991, now U.S. Pat.No. 5,411,473, which is a divisional application of U.S. Ser. No.07/478,655, filed Feb. 12, 1990, and entitled "Medical Valve," now U.S.Pat. No. 5,071,408, which is continuation-in-part application of U.S.patent application Ser. No. 07/255,070, entitled Self-RegulatingPressure Control Glaucoma Valve, filed Oct. 7, 1988, now abandoned. Allof these related applications are incorporated herein by reference andmade a part of this application.

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention relates to medical devices which are implanted in thehuman body, particular to a valve which is easy to manufacture, performsreliably, is easy to surgically implant in the human body, and willremain functional for the life of the patient in which it is implanted.The valve of this invention has a unique shape that reduces thepossibility that the body will reject the valve when implanted in an eyeof a glaucoma patient.

2. Background Discussion

Medical valves are used for many different types of applications. Onesuch application is to treat glaucoma by allowing aqueous humor to flowfrom the intraoccular chamber of the eye to relieve excess pressure.Thomas C. White in U.S. Pat. No. 4,554,918 has suggested one type ofglaucoma valve where the aqueous humor flows from the intraoccularchamber through a tube into an external reservoir. The end of the tubein communication with the reservoir has a small opening in its end. Thesmall opening provides a great deal of resistance to flow of the aqueoushumor which is highly viscous. The White valve provides for flow in onlyone direction, namely, from the intraoccular chamber of the eye to theexternal reservoir. Upon being filled, the reservoir is pressed by thepatient to force the aqueous humor contained in the reservoir throughanother tube into the body of the patient where it is absorbed.

Another device used to treat glaucoma is discussed by Anthony C. B.Molteno in U.S. Pat. No. 4,457,757. This device includes a plate havinga tube that extends into the intraoccular chamber. The aqueous humorfrom the intraoccular chamber flows onto the surface of the plate and isabsorbed by the body. The Molteno plate does not have any pressurecontrolling mechanism, and it is only a device for releasingintraoccular pressure.

Both of these devices have been used to treat glaucoma, but the Whitevalve suffers from the disadvantage that the patient must manually pressthe reservoir in order to force the aqueous humor collected in thereservoir to escape and be absorbed by the body. Moreover, although theWhite valve is designed to open when the intraoccular pressure becomesexcessive, the valve's structure is not reliable, because it dependsupon a tiny opening in the end of the tube which is very small indiameter and can easily be clogged by particulates. Nor is the Whitevalve very sensitive, because it does not respond to slight changes inpressure to open and close. The Molteno plate overcomes the objectionsof the manually actuated reservoir, however, it does not employ a valveand could lead to hypotony, that is, the loss of aqueous humor withinthe intraoccular chamber of the eye.

Glaucoma Valve

The valve disclosed in the above-identified U.S. Pat. No. 5,071,408(herein referred to as the Glaucoma Valve) has many features thatdistinguish it from White and Molteno.

The Glaucoma Valve uses a membrane under tension to form a chamberhaving an elongated, slit-like opening therein. The membrane responds toslight changes in pressure to expand or contract to open or close theopening. When opened, it provides a wide open mouth with parted lipsthat allows for free flow of fluid though it without any substantialresistance to fluid flow. This feature also substantially reduces thelikelihood that the opening will be clogged by particulates. Typicallythe width of the slit-like opening ranges between 2.500 and 3.500millimeters, preferably between 2.725 and 2.750 millimeters.

The Glaucoma Valve has a chamber preferably with a trapezoidalconfiguration to provide a narrow side and a wide side. The slit-likeopening is essentially coextensive with the narrow side and an inlettube is connected to the wide side. Fluid flows into the chamber throughthe inlet tube. Depending on the fluid pressure within the chamber, theslit-like opening will be either opened or closed. The pressure in thechamber must, however, exceed the tension in the membrane in order toexpand the membrane means to open the slit-like opening.

The trapezoidal configuration of the chamber renders the valve highlyresponsive to slight changes in pressure. The fluid as it enters thechamber at the wide side first flows into a space which has a relativelylarge cross-sectional area compared to the cross-sectional area of thechamber adjacent to the slit-like opening in the narrow side. This isimportant because it makes the Glaucoma Valve sensitive to slightchanges in pressure and allows it to open very briefly to reduce thepressure in the chamber. When the fluid pressure in the chamber justequals the pressure created by the tension in the membrane means, theslit-like opening is closed. As soon as this pressure increases due toadditional fluid flowing into the chamber along its wide side, themembrane means expands and the fluid flows from the slit-like opening.The velocity of the fluid flowing from the opening is substantiallyhigher than the velocity of the fluid entering the chamber at its wideside to decrease quickly the pressure in the chamber and close theGlaucoma Valve. The relative high velocity with which the fluid exitsthe opening aids in flushing the chamber and reduces the possibility ofback flow. Since the rate at which aqueous humor is formed in theintraoccular chamber of the eye is very slow, approximately one dropevery three hours, slight increases in volume of aqueous humor result inthe valve of this invention opening momentarily and then closing. Theseunique features of the valve of this invention allow pressure in thechamber to be maintained at 10 millimeters (mm) of mercury (Hg), with anincrease in pressure of 0.5 mm of Hg opening the valve. As soon as theintraoccular pressure stabilizes at 10.0 mm of Hg, the valve is totallyshut off to prevent the further flow of aqueous humor from draining fromthe intraoccular chamber. Thus, the cornea never loses its dome-likeshape and hypotony is avoided.

The Glaucoma Valve uses two plates which hold between them in tensionoverlying membrane members which form between them the chamber. Theslit-like opening is along adjoining, overlapping edges of the membranemembers. Preferably, the membrane members are simply two halves of athin sheet of silastic material which is folded over upon itself. Thetwo plates each include interlocking members that, upon the plates beingpressed together, engage to place the membrane members disposed betweenthe plates in tension. By adjusting the size and positions of theinterlocking members, the tension may be varied to provide differentvalve designs which open in response to different pressures. Moreover,once the tension is established for a specific valve design, thisGlaucoma Valve is easily reproducible, allowing this specific valvedesign to be mass produced without any significant variation in itspressure response from one valve to another. The interlocking membersfor any specific valve design apply essentially equal tension across theentire width of the membrane. This is desirable to insure repeatableperformance. Each of the plates include therein identical trapezoidalshaped depressions. The plates are aligned with each other when joinedtogether so that the two trapezoidal depressions are in registration.The trapezoidal configured chamber is formed when fluid flows betweenthe membranes to expand them outwardly, pushing the membranes outwardlyagainst the walls of the depressions.

The Glaucoma Valve is adapted to be attached to the eye to provide ahinge-like, cantilever action. A pair of suturing holes are provided onthe main body of the Glaucoma Valve, one hole on each side of the inlettube. When the Glaucoma Valve is placed on the eye, two stitches aremade, one through each hole to secure the valve to the sclera of theeye. This creates a large distribution area adjacent the Glaucoma Valveto be used for absorption of the aqueous humor.

SUMMARY OF THE INVENTION

The present invention is a medical device such as a valve which may beimplanted in the human body. This device has a uniquely shaped enhancingits ability to treat glaucoma successfully. This invention is animprovement in the Glaucoma Valve, but may be used in other medicaldevices.

There are several features of this invention, no single one of which issolely responsible for its desirable attributes. Without limiting thescope of this invention as expressed by the claims, its more prominentfeatures will now be discussed briefly. After considering thisdiscussion, and particularly after reading the section of theapplication entitled "DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT,"one will understand how the features of this invention provide itsadvantages, which include the ability to form a thin walled blebsurrounding the valve.

The first feature of the improved valve of this invention is that itincludes a body member holding a pair of overlying membranes in tensionto form therebetween a chamber, with the membranes providing anelongated, slit-like opening therebetween. An inlet tube is incommunication with the chamber at a point remote from the opening. Thebody member employs a distribution plate having an enlarged surfacearea. Aqueous humor is caustic and the body can only gradually absorbit. This absorption process is promoted if this aqueous humor isdistributed over a relative large surface. Because of the unique shapeof the valve of this invention a extra large absorption surface area isprovided. The enlarged area of the distribution plate serves thispurpose. Typically the surface area of the distribution plate rangesbetween 0.2 and 0.4 square inch.

A bleb is formed around the valve, and the aqueous humor is absorbedinto the body by seeping through pores in the bleb. Thick skinned blebsretard this absorption process. It would be desirable if the bleb wasmore porous to facilitate drainage of the aqueous humor. The secondfeature of this invention is that the improved valve is shaped so that ableb is formed which is more porous than normal. This is accomplishedwhen the body member has a tapered end and is sized to enable the bodymember to be inserted between the major and minor rectus muscles of theeye ball. Preferably, the body member has a generally ovalconfiguration, and a concave surface adapted to conform to the exteriorof an eye ball on which the body member rest when implanted.

This invention also includes a method for treating glaucoma by drainingthe intraoccular chamber of the eye of a patient using the valve of thisinvention. The method includes the steps of

(a) providing the valve,

(b) positioning the valve on an eye ball of the patient with the concavesurface resting on the exterior of the eye ball and the body memberbetween a major rectus muscle and a minor rectus muscle of the eye balland the taper end of the body member pointed towards the anterior of theeye ball,

(c) inserting the one end of inlet tube into the intraoccular chamber toenable fluid to drain through the slit-like opening onto the enlarged,collection surface area, with a bleb forming over said enlarged,collection surface area which due to the oval shape of the body memberallows for this fluid to be quickly absorbed by the patient's body, and

(d) attaching the valve to the eye ball.

DESCRIPTION OF THE DRAWING

The preferred embodiment of this invention illustrating all of itsfeatures will now be discussed in detail. This embodiment depicts thenovel and unobvious features of the medical valve of this invention. Thedrawing accompanying this application, which is for illustrativepurposes only, includes the following figures (FIG.), with like numeralsindicating like parts:

FIG. 1 is an exploded perspective view of the medical valve of thisinvention.

FIG. 2 is a perspective view of an unfolded membrane, with a tubeextending outwardly from its backside.

FIG. 2A is a perspective view of the membrane folded to form atrapezoidal chamber, showing the slit-like opening with its lips partedto allow fluid to flow from the chamber.

FIG. 3A is a cross-sectional view showing the two plates positioned tobe press together to hold the folded membrane therebetween.

FIG. 3B is a cross-sectional view showing the two plates connectedtogether and holding the folded membrane therebetween.

FIG. 4 is a plan view looking at the internal surface of the top plateused in the medical valve of this invention.

FIG. 5 is a cross-sectional view taken along 5--5 of FIG. 4.

FIG. 6 is a cross-sectional view along 6--6 of FIG. 4.

FIG. 7 is a plan view showing the internal surface of the base plateused in the medical valve of this invention.

FIG. 8 is a cross-sectional view taken along line 8--8 of FIG. 7.

FIG. 9 is a cross-sectional view taken along 9--9 of FIG. 7.

FIG. 10 is an enlarged cross-sectional view showing the way the tube isconnected to the membrane.

FIG. 11 is a perspective view a novel surgical instrument of thisinvention used to insert the tube from the valve into the intraoccularchamber of the eye.

FIG. 12 is a schematic view showing the valve of this invention beingsurgically implanted in the eye of a patient using the instrument shownin FIG. 11.

FIG. 13 is an enlarged perspective view of the medical valve of thisinvention partially implanted into the eye of the patient.

FIG. 14 is a perspective view of the valve implanted in the eye of apatient.

FIG. 15 is a cross-sectional view of the eyeball of the patient with themedical valve of this invention implanted therein.

FIG. 16 is a front elevational view of an eye ball with the medicalvalve of this invention positioned at the desired location on theexterior of the eyeball.

FIG. 17 is an exploded perspective view of an alternate embodiment ofthis invention having a unique shape.

FIG. 18 is a plan view of the base plate used in the valve shown in FIG.17.

FIG. 19 is a cross-sectional view taken along line 19--19 of FIG. 18.

FIG. 20 is a cross-sectional view taken along line 20--20 of FIG. 18.

FIG. 21 is a cross-sectional view taken along line 21--21 of FIG. 18.

FIG. 22 is a perspective view showing the valve of FIG. 17 attached tothe exterior of an eye and located so that its tapered end is positionedbetween eye muscles.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As best illustrated in FIG. 1, the medical valve 10 of this inventionincludes a base plate 12, a flexible, siliconized rubber membrane 14, atop plate 16, and a siliconized rubber inlet tube 18. The membrane 14 isfolded to form a pair of essentially identically shaped membrane members14a and 14b. The membrane members 14a and 14b are placed between alignedand spaced apart top plate 16 and base plate 12 as illustrated in FIG.3A and these plates are pressed together and interlocked as illustratedin FIG. 3B to hold the membrane members in position. The inlet tube 18extends from the plates 12 and 16 so that its free end 18a may besurgically inserted into the intraoccular chamber 20 of the eye asillustrated in FIG. 15.

The membrane 14 is originally in a non-folded condition as shown in FIG.2, and it has a hourglass-like shape narrowing at the central section15a and then expanding outwardly therefrom in both directions. Themembrane 14 has a thickness ranging between 0.004 and 0.007 inch,preferably between 0.005 and 0.006 inch. There is a central opening 15bin the member 14 in which the inlet tube 18 is inserted and four spacedapart openings 14c, 14c', 14d, 14d', 14e, 14e', 14f, and 14f' along itsopposed irregular sides 22 and 24. These holes 14c through 14f and 14c'through 14f' have a diameter of approximately 0.02 inch. A suitablesiliconized rubber material for use as the membrane 14 and inlet tube 18is made by Dow Corning Corporation, Medical Products, identified by thetradename Silastic, product No. 602-105.

The base plate 12 has a generally hexagonal configuration with a raisedridge 26 extending above the perimeter of the plate. The plate 12 isdivided into a forward section 28 and a rear section 30. The portion ofthe ridge 26 surrounding the rear section 30 forms a distribution area32 which receives aqueous humor from the eye. This distribution area 32preferably ranges between about 0.119 and about 0.200 square inch.

The forward section 28 is raised above the distribution area 32 and itincludes a centrally located depression 34 of a generally trapezoidalconfiguration. On each side of this depression, running alongsubstantially its entire length, are two grooves 36 and 38. At the oneend 34a of the depression 34 is a semi-cylindrical indentation 40 whichreceives the tube 18 and on each side of this indentation are two tinyorifices 42 and 44 having a diameter of about 0.02 inch. On the outsideof each of the two grooves 36 and 38 are a pair of raised pins 46 and 48and 50 and 52, respectively.

The top plate 16 is a four-sided member having a centrally locatedtrapezoidal depression 54 therein with a semi-cylindrical indentation 56along its one side 16a. There are a pair of elongated finger elements 58and 60 extending downwardly which interlock, respectively, in thegrooves 36 and 38 in the base plate 12 when the two plates are pressedtogether. There are pairs bores 62 and 64 and 66 and 68, respectively,of on the outside of each of the fingers 58 and 60 which receive thepairs of pins 46 and 48 and 50 and 52 in the base plate 12 when the topplate 16 and base plate are aligned and pressed together. There are twosmall orifices 70 and 72 in the top plate 16 which are in registrationwith the orifices 42 and 44 when the base plate and top plate are joinedtogether.

Both the top and base plates 12 and 16 have a segmented spherical shapeso that they conform to the curvature of the eye ball. Both the plates12 and 16 and the tube 18 are made of a material that will not berejected by the body. Suitable materials from which to make the plates12 and 16 are siliconized rubber, polypropylene, and polymythlmethylacrelate (PMMA).

FIG. 10 shows the way that the inlet tube 18 is bonded to the membrane14. With the membrane 14 folded inwardly upon itself, it is placedbetween the top plate 16 and base plate 12 and these plates areinterconnected together. This inlet tube 18 is inserted into the centralopening 15b, with its outwardly extending section being placed betweenthe indentations 40 and 56, respectively, in the plates 12 and 16. Asshown in FIG. 10, an adhesive 17 is used to bond the tube 18 and themembrane 14. An example of a suitable adhesive is medical grade SilasticA made by Dow Corning Corporation.

One of the unique features of this invention is that, when the plates 12and 16 are joined together, the membrane members 14a and 14b formbetween them in the space between the trapezoidal indentations 34 and 54a chamber 21. At the inward edges 74 (FIG. 1) of these members 14a and14b there is formed adjoining lips 23 and 25 that provide an elongated,slit-like opening 19 in the chamber 21 that is unlikely to be clogged byparticulates. This slit-like opening 19 is normally closed because ofthe tension in the membrane members 14a and 14b, but opens when thepressure across the opening exceeds a predetermined value. When used asa glaucoma valve, the differential in pressure must exceed 10millimeters of mercury before the lips 23 and 25 part to open the valve.These lips 23 and 25 close immediately when the pressure differential isless than 10 millimeters of mercury.

The chamber 21 formed between the members 14a and 14b has a trapezoidalconfiguration. This is important because it makes the valve 10 verysensitive to slight changes in pressure. Due to the trapezoidalconfiguration of the chamber 21, the area of the inlet end of thechamber is larger than the area of the outlet end of the chamber. Thiscreates a Bernoulli effect. Specifically, the incoming fluid fills thechamber 21 and the pressure increases to the point where the lips 23 and25 of the membrane members 14a and 14b forming the slit-like opening 19spread apart. The fluid then flows through the parted lips 23 and 25 ofthe membrane members 14a and 14b at a velocity which is substantiallyhigher than the velocity of the fluid entering the chamber at the inletend. Thus, the pressure is reduced almost instantaneously to close thevalve 10. The incoming fluid causes the pressure in the chamber 21 toonce again increase and the valve 10 again opens, with the pressure inthe chamber deviating only slightly from a nominal value corresponding,for example, to the desired pressure to be maintained in theintraoccular chamber of the eye, namely 10 mm of Hg.

The medical valve 10 of this invention is easy to assemble. The membrane14 is simply folded over and placed between the base plate 12 and topplate 16 with these plates aligned and in registration so that, whenthey are pushed together, the interlocking members, including the pins46, 48, 50 and 52 and bores 62, 64, 66, and 68, and grooves 36 and 38,and fingers 58 and 60, clamp the membrane members 14a and 14b firmlybetween the plates to form the valve body 11. The pins 46, 48, 50, and52 pass through the holes 14c through 14f' upon joining the plates 12and 16 together. Ultrasonic welding bonds the plates 12 and 16 together.

As best illustrated in FIGS. 11 through 15, the medical valve 10 of thisinvention may be inserted into the eye of a patient by the use of aunique surgical instrument 80 consisting of a handle 82 and needle-likebody member 84 having an elongated slot 86 in a side wall 84a of theneedle-like member. The needle-like body member 84 terminates at theshape tip 85 which is beveled. The slot 86 allows the inlet tube 18 tobe placed within the needle-like body member 84 lengthwise along aU-shaped channel 88 running along the longitudinal axis of theneedle-like body member. The slot 86 and channel 88 each have a widththat is essentially equal to the diameter of the inlet tube 18 so that,with the inlet tube lying in the channel, there is a snug, friction fit.Thus, fluid enters the open end of the tube and flows through the tube18 rather than between the wall of the channel 88 and the wall of thetube. For use with the glaucoma valve 10 of this invention, the slot 86has a width from 0.025 to 0.028 inch and a length of from 1.1 to 1.25inch. The dimensions of the slot and channel may, however, be varieddepending on the application.

To use the instrument of this invention, with the tube 18 in the channel88, the surgeon simply inserts the shape tip 85 of the instrument 80into the eyeball to bring the inlet tube 18 into the intraoccularchamber 20 of the eye. The surgeon then simply withdraws the instrument.As he does this, the inlet tube 18 remains in the eye, with thesurrounding tissue grasping the inlet tube as the instrument 80 iswithdrawn. The valve body 11 is then placed beneath a sclera flap 90(FIGS. 13 and 14) which is cut from the exterior of the eye ball. Theflap 90 is then placed over the valve body 11 and then sutured inposition as shown in FIG. 14. The aligned orifices 42 and 44 and 70 and72, respectively in plates 12 and 16, allow the surgeon to suture thevalve body 11 to the eye ball. This allows any overflow of aqueous humorflowing from distribution area 32 to seep beneath the valve body 11.

Within a short period of time after the operation, a bleb is formedaround the valve body 11. A bleb is a tissue membrane that traps theaqueous humor collecting in the distribution area 32 or under the valvebody 11. This entrapped fluid is then slowly absorbed into the body ofthe patient. With the valve 10 implanted in the patient, as illustratedin FIGS. 15 and 16, pressure within the intraoccular chamber 20 forcesthe aqueous humor through the inlet tube 18 into the trapezoidalchamber. When the chamber is filled and the pressure in the intraoccularchamber 20 exceeds 10 millimeters of mercury, the lips 23 and 25 formedby the overlying members 14a and 14b spread apart, but only for suchtime period as this differential pressure exists. Once the differentialpressure is below 10 millimeters of mercury, the membrane members 14aand 14b, being under tension, close off the slit-like opening 19automatically so that aqueous humor no longer will escape from theintraoccular chamber 20, thereby avoiding hypotony.

Alternate Embodiment

The alternate embodiment of this invention, the valve 100, is similar inmany respects to the valve 10 depicted in FIG. 1, with the principaldifference being that this new valve 100 has a uniquely shaped bodymember 101. The valve 100 has a base plate 112, a top plate 116 with afolded membrane 114 sandwiched between these plates. An inlet tube 118extends outward from the folded portion of the membrane 114, with theoverlapping membrane members 114a and 114b being held in position bypins 146, 148, 150, and 152 which extend through openings 115 in themembrane and into bores 162, 164, 166, and 168 in the top plate 116.Finger elements 158 and 160 extending from the bottom of the top platesare wedged into grooves 136 and 138 in the forward section 128 of thebase plate. This causes the membrane 114 to stretch, placing it intension so that a slit-like opening is formed between the edges of theoverlapping membrane members 114a and 114b. There are trapezoidaldepressions 134 and 154, respectively, in the base plate 112 and the topplate 116. This creates a trapezoidal-shaped chamber (not shown) betweenthe overlapping membrane members 114a and 114b into which fluid exitingthe inlet tube 118 flows. There are a pair of extensions 169 and 171along the anterior edge 97 of the base plate 112 with orifices 170 and172 therein that allow the valve 100 to be sutured to the an eyeball asdepicted in FIG. 22.

In accordance with one of the principal features of this embodiment ofthis invention, the body member 101 has a generally oval shape as bestillustrated in FIG. 18. The base plate 112 is in the form of a segmentedsphere, providing a concave interior surface 112b which rest against theeyeball when the valve 100 is implanted in, for example, a glaucomapatient. As with the Glaucoma Valve, the inlet tube 118 has its remoteend inserted into the ocular chamber of the eye allowing the aqueoushumor to drain from the eye when pressure in the ocular chamber isexcessive. The valve 100 opens under the influence of this excessivepressure to allow the aqueous humor to drain onto the enlarged surfacearea 113 surrounded by the raised ridge 126 on the base plate 112.

As best depicted in FIG. 17, the posterior edge 99 of the valve 100 istapered so that it fits easily between the major rectus muscle 150 andminor rectus muscle 151 of the eyeball. This allows the valve 100 to beinserted as shown with the tapered end pointing towards the posterior ofthe eyeball. Typically, the valve 100 has a width ranging between 7 and13 millimeters, and a length ranging between 10 and 16 millimeters. Thisallows for the provision of a substantially increased surface area 113,maximizing utilization of the area between the major and minor rectusmuscles in the most efficient manner, for example the surface area 113is about 0.3 square inch. The anterior edge 97 of the valve isapproximately 8 to 12 millimeters from the limbus when the valve ispositioned as illustrated in FIG. 22.

There is a ridge 126 surrounding the enlarged surface area 113 whichassist in formation the bleb 90. The ridge 126 has an exterior wall 126awhich tapers inward towards the enlarged surface area 113. Thus, thewall of the bleb will form a complementary angle also lying inwardtowards the enlarged surface area 113. The ridge 126 also retains fluidon the enlarged surface area 113.

As with the valve illustrated in FIG. 1 and FIG. 15, a sclera flap 90ais cut from the exterior of the eyeball and the valve 100 is placedunderneath this flap. This forms a bleb which surrounds the valve 100.Because of the difference in length versus the width of the valve 101,i. e., its the oval configuration, the bleb is more porous than if thevalve was circular. Consequently, the aqueous humor collected on theenlarged surface area 113 more readily absorbs into the patient's body.

In accordance with the method of this invention, the valve 100 is placedbetween the major and minor rectus muscles as opposed to inserting thevalve underneath these muscles as is the case with some ocular implantdevices. The placement of the valve as depicted in FIG. 22 is highlydesirable, since it minimizes the problems associated with strabism, oreye squinting, which is frequently caused when ocular devices arepositioned underneath the major and minor rectus muscles.

SCOPE OF THE INVENTION

The above presents a description of the best mode contemplated ofcarrying out the present invention, and of the manner and process ofmaking and using it, in such full, clear, concise, and exact terms as toenable any person skilled in the art to which it pertains to make anduse this invention. This invention is, however, susceptible tomodifications and alternate constructions from that discussed abovewhich are fully equivalent. Consequently, it is not the intention tolimit this invention to the particular embodiment disclosed. On thecontrary, the intention is to cover all modifications and alternateconstructions coming within the spirit and scope of the invention asgenerally expressed by the following claims, which particularly pointout and distinctly claim the subject matter of the invention:

I claim:
 1. A medical valve includinga body member formed, at least inpart, by a pair of plates, one of said plates having an enlarged surfacethat serves to collect fluid escaping from the opening, said body memberholding a pair of overlying elastic membranes in tension to formtherebetween a chamber, said membranes providing an elongated, slit-likeopening therebetween, and an inlet tube in communication with thechamber at a point remote from the opening, said chamber having apredetermined configuration so that its cross sectional area near thepoint where the inlet tube is in communication with the chamber islarger than the cross sectional area of the chamber near the opening. 2.The medical valve of claim 1 wherein the chamber has a trapezoidalconfiguration.
 3. The medical valve of claim 1 wherein said enlargedsurface has a surface area ranging between 0.2 and 0.4 square inch.
 4. Amedical device for draining the intraoccular chamber of the eyeincludinga body member formed, at least in part, by a pair of plates,one of said plates having an enlarged, collection surface area thatserves to collect fluid escaping from the intraoccular chamber of theeye, said body member having a tapered end and size to enable the bodymember to be inserted between muscles attached to the eye ball, and aninlet tube having one end adapted to be placed in communication with theintraoccular chamber to enable fluid to drain and another end incommunication with the collection area at a point remote from theintraoccular chamber of the eye, said chamber having a predeterminedconfiguration so that its cross sectional area near the point where theinlet tube is in communication with the chamber is larger than the crosssectional area of the chamber near the opening.
 5. A medical device ofclaim 4 where the body member includes a valve having a pair ofoverlying membranes in tension to form therebetween a chamber, saidmembranes having overlapping edges that provide an elongated, slit-likeopening therebetween, and an inlet tube in communication with thechamber at a point remote from the opening.
 6. The device of claim 5where the chamber has a trapezoidal configuration.
 7. The device ofclaim 5 where said enlarged surface has a surface area ranging between0.2 and 0.4 square inch.
 8. The device of claim 4 where said body memberhas a concave surface adapted to conform to the exterior of an eye ballon which the body member rest when implanted.
 9. The device of claim 4where said body member has a generally oval configuration.
 10. A medicaldevice for draining the intraoccular chamber of the eye includinga bodymember including a plate element having an enlarged, collection surfacearea that serves to collect fluid escaping from the intraoccular chamberof the eye, said body member having a generally oval shape, a concavesurface adapted to conform to the exterior of an eye ball on which thebody member rest when implanted, and a tapered end and size to enablethe body member to be inserted between muscles attached to the eye ball,said body member holding a pair of overlying membranes in tension toform therebetween a chamber, said membranes providing an elongated,slit-like opening therebetween, and an inlet tube in communication withthe intraoccular chamber at a point remote from the opening, and aninlet tube having one end adapted to be placed in communication with theintraoccular chamber to enable fluid to drain and another end incommunication with the collection area at a point remote from theintraoccular chamber of the eye.
 11. The medical device of claim 10where the body member is formed, at least in part, by of a pair ofplates, one of said plates being said plate element having the enlargedsurface that serves to collect fluid escaping from the opening.
 12. Themedical device of claim 10 wherein the chamber has a predeterminedconfiguration so that its cross sectional area near the point where theinlet tube is in communication with the chamber is larger than the crosssectional area of the chamber near the opening.
 13. The medical deviceof claim 12 wherein the chamber has a trapezoidal configuration.
 14. Themedical device of claim 10 wherein said enlarged surface has a surfacearea ranging between 0.2 and 0.4 square inch.
 15. A method for treatingglaucoma by draining the intraoccular chamber of the eye of a patient,including the steps of(a) providing a device havinga body memberincluding a plate element having an enlarged, collection surface areathat serves to collect fluid escaping from the intraoccular chamber ofthe eye, said body member having a generally oval shape, a concavesurface adapted to conform to the exterior of an eye ball on which thebody member rest when implanted, and a tapered end and size that enablesthe body member to be inserted between muscles attached to the eye ball,said body member holding a pair of overlying membranes in tension toform therebetween a chamber, said membranes providing an elongated,slit-like opening therebetween, and an inlet tube in communication withthe intraoccular chamber at a point remote from the opening, and aninlet tube having one end adapted to be placed in communication with theintraoccular chamber to enable fluid to drain and another end incommunication with the collection area at a point remote from theintraoccular chamber of the eye, (b) positioning the device on an eyeball of the patient with the concave surface resting on the exterior ofthe eye ball and the body member between a major rectus muscle and aminor rectus muscle of the eye ball and the taper end of the body memberpointed towards the anterior of the eye ball, (c) inserting said one endof inlet tube into the intraoccular chamber to enable fluid to drainthrough the slit-like opening onto the enlarged, collection surfacearea, with a bleb forming over said enlarged, collection surface areawhich due to the oval shape of the body member allows for said fluid tobe quickly absorbed by the patient's body, (d) attaching the device tothe eye ball.
 16. A medical valve includinga body member holding a pairof overlying elastic membranes in tension to form therebetween achamber, said membranes providing an elongated, slit-like openingtherebetween, which is normally in a closed position and opens when thepressure in the chamber exceeds a predetermined pressure and returns tothe closed position when the pressure in the chamber is below saidpredetermined pressure, and an inlet tube in communication with andconnected to the chamber at a point remote from the opening.